A "tripledemic" collision of flu, COVID and RSV cases on the horizon

• RSV is a common respiratory virus among children that produces common cold symptoms.
• For most, a mild case lasts about two weeks. But some people, especially those with pre-existing health conditions, may suffer from more severe cases that can lead to hospitalization, according to the CDC.

By the numbers: RSV cases detected by PCR tests have tripled nationally in the last two months, per the CDC.

• U.S. case numbers have already reached 2021's peak levels.

Zoom in: Guliz Erdem, an infectious disease physician at Nationwide Children's Hospital says the hospital is full. Many — but not all — are RSV patients.

• "We are in 'surge mode' but not in 'panic mode'," Erdem tells Axios. "The timing is a bit different. I wouldn't say we are seeing more RSV this year but we are seeing it."
• Erdem says it's too early to tell whether this year will rival 2019-20, which she said was a substantial peak season of RSV.

How we got here: In pre-pandemic years, RSV would make its rounds in the fall and winter before going away in the summer, according to the Wall Street Journal.

• COVID-19 shifted the pattern, causing a dip in RSV as the coronavirus bullied its way through the population.

Yes, but: Erdem says that during the pandemic, people were diligent about practices like hand-washing, masking and avoiding large gatherings.

• These all could have potentially contributed to a drop in illnesses like RSV over the last two years.
• People returning to pre-pandemic ways of life could explain the early surge of cases.

What we're watching: The coming months are when illnesses historically peak, especially now there are little to no travel or masking restrictions.

• It is expected to be a rough season for sickness, with some predicting a "tripledemic" collision of flu, COVID and RSV cases on the horizon.